1994.5 C3000 frankentruck

[1Matthias]

So with regards to the difference between 4L60E and 4L80E column shifters....it turns out that if you use a 4L60E shifter assembly on a 4L80E, you will cause the linkage to massively bind and stick in one position: *drive*. Not knowing this, on Christmas day I gave myself one hell of a present: a story for the ages. Very quickly several lessons were learned. One: hydroboost brakes suck without assist. Two: a 350 with 4.10s has enough torque to hop wheel chocks quite merrily at idle with no weight on the rear axle. Three: a utility bed falling off stands when you run into it with a truck makes a distinct noise. Four: the aforementioned difference between 4L60E and 4L80E shifters....

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Oops. In good news, the fall was slow and graceful so there was very little damage to anything involved other than my ego and underwear...

 

[1Matthias]

After sourcing a 4L80E specific linkage from a local junkyard and regaining full control over all gears, work continued. I invited a few friends over and we made a party of installing the bed, which went...much smoother than removal somehow.

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And at this point I got hitched...trailer hitched specifically. For whatever reason Stahl mounted the rear of the bed to the brackets that hold the trailer hitch and bumper to the frame....so I had to get creative with the fab work.

 

[1Matthias]

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I reused and modified the factory frame brackets off the 3500, cut a hole in them for some 3"x3/8" wall squaretube, and then welded it all together....

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[1Matthias]

While all this was happening, I also dug into the 350. The reason I got the 3500 so cheap was the previous owner thought it had a blown head gasket: the coolant kept vanishing and it was misfiring badly. Well, there was also *no trace* of water in the oil and no steam from the exhaust which told me that there'd been a major misdiagnosis - and my suspicions were correct. The previous owner had been running straight tap water as coolant and the sheet metal plate on the back of the water pump was rusted out: but because it was straight water, it just blew back onto the block and evaporated. New water pump cleared that up and rendered the cooling system sound. As for the misfire....well...have a look at this distributor cap:

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With a new cap, rotor, plugs, and wires as well as cleaning the injectors and throttle body, it runs like a *dream*. Oh, and no sign of a head gasket issue.

 

[GrimsterGMC]

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I reused and modified the factory frame brackets off the 3500, cut a hole in them for some 3"x3/8" wall squaretube, and then welded it all together....

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I am really impressed with your welding, this is obviously something you do a lot of.

 

[1Matthias]

I am really impressed with your welding, this is obviously something you do a lot of.

Thank you - I actually quite a few years back went through welding classes but am a bit out of practice at the moment. This has been a fun reintroduction.

 

[Intragration]

x2 on the welds, and very cool project overall. If you did a good job on all the connections when marrying those harnesses, I don't know if I'd be pulling a perfectly good harness out and making a new one from scratch...but hey, it's something to pass the time.

 

[1Matthias]

Thank you for the kind words RE: welding! And as for the wiring harness: although there's nothing particularly functionally wrong with it, I dislike having a greater number of connections or joins in a harness than absolutely needed: most wiring issues are down to connections after all, so.
Also a bit out of order, but: Not being one to do things the logical route, I decided the first major test of the mechanical and electrical side of this project should be.....towing the parts truck for the HVAC parts ~60 miles home, and I'm more than pleased to report that it made it safe and sound with a '94 C2500 NA 6.5 in tow. Actually did shockingly well on fuel as well, which is an encouraging sign.
Now, back in order: one of the next steps was the tail lights. See, I have a personal pet peeve: combined brake and turn lights. So I broke out the diagrams and thinking cap and came up with...this.

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In effect, I completely separated the brake and turn signals, with the exception of turning the outer brake light off when the signal is running. All in all, I'd say it turned out pretty well:

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Oh, and despite all this I retained the 100% factory appearing controls. This might be a controversial modification, but I much prefer amber turn signals to red and having brake and turn signals separated.

 

[Intragration]

...as for the wiring harness: although there's nothing particularly functionally wrong with it, I dislike having a greater number of connections or joins in a harness than absolutely needed: most wiring issues are down to connections after all, so.

If you replace the harness, you're eliminating a bunch of good solder joints, and introducing new pins and connectors (connections) to replace ones that are working fine. Just something to consider.